Dental implement.



G. O. MURRAY.

DENTAL IMPLEMENT.

' APPLICATION FILED SEPT. 15. 1908.

Patented Jan.12,1909.

' INVENTOR 671M159 6'. MUFRfl/j BY WWW 6.

w/rAlEssgs M A TTOHNE Y S CHARLES O..MURP-A Y, OFHUNTINGDO N, TENNESSEE.

DENTAL IMPLEMENT.

Specification of Letters Patent.

Patented 31111.12, 1909.

Application filed. September 15, 1908. Serial No. 453,094.

To all whom it may concern:

Be it known that I, CHARLES C. MURRAY, a citizen of the United States, residing at Huntingdon, in the county of Carroll, State of Tennessee, have invented an Improvement in Dental Implements of which the following is a specification.

My invention is an improved implement or tool for use in inlay work.

As is well known to those acquainted with the dental art in its present development, inlays consisting of plugs of porcelain, gold, glass, vulcanized rubber or other suitable material, are formed for filling tooth cavities, the same being cemented therein. One of the usual methods for producing cast inlay work, consists in pressing wax into the tooth cavity, which is to be filled or plugged, then a metal pin is slightl heated and inserted in the wax that fills the cavity. Next the pin and the wax are chilled by a jet of cold water, by which the pn is'set and held in the wax with due firmness. This enables the dentist to remove the wax model while adhering to the pin. The dentist then makes a wax cone of the desired size, the same being formed around the pin just above the wax model. The whole, that is to say, the cone, the pin, and the model, are then inserted to the required depth in some suitable fire-proof compound. The latter is then subjected to heat, whereby the wax is melted and thus removed from the investment, a hole being left in the top of the latter for the reception of the plastic material or metal which is to be heated for filling the space previously occupied by the wax model. By my invention, the use of such wax cone is dispensed with and thus an important saving in time and labor is effected.

In carrying out my invention, I employ a hollow conical metal body having a hole in the apex for reception of the pin which is to hold the wax model, and the body of the cone is provided with a handle and a clasp adapted to secure the pin detachably, all as hereinafter more particularly set forth.

In the accompanying drawing, Figure 1 is a perspective view of the entire implement, the pin being separated from the other parts. Fig. 2 is a side view of the entire implement, the pin being held in its normal position. Fig. 3 is a longitudinal section of the parts in the position shown I in Fig. 2. Fig. 4c is a cross section on the line 4.-.4 of Fig. 2. p

The numeral 1 indicates the hollow, conical,'metal body of the implement, the same being provided at its apex with a hole 2 adapted to receive the shank 8 of the pin. The latter is provided at itssouter end with a conical enlarged head 3, and the shank is also provided with a circumferential groove 3". The 'cone 1 is provided interiorly, at about the middle of its length, with a crossbar or bracket 4 which has a central opening adapted to receive the shank 3 of the pin and in which the same may slide freely. A combined handle and shank is connected with the cross bar I. The same consists of a plate 5 which is formed rigidly with the cross bar, and a pivoted spring clasp 6, whose inner end is curved inward to form a catch 6" adapted to engage the circumferential groove 3 in the pin shank The part 6 is pivoted centrally to the plate 5, and a spring 7 is interposed between their outer ends so that the catch 6 is held normally engaged with the pin, the head 3 of the latter abutting the apex of the cone, as shown in Figs. 2, 3.

I11 the practical use of my invention, it is manipulated as follows: The head 3* of the pin having been inserted in the wax model and secured therein, it, with the wax model adhering, is inserted in the cone 1 in the manner indicated in Figs. 2, 8. As is apparent, when thus inserted the shank of the pin is automatically engaged by the catch 6 and thus the adhering model is held securely in place, the base of the head 8 abutting the edge of the hole 2 in the cone. The whole is then invested in some plastic fire-proof compound, and as soon as the same has set, the cone and pin are withdrawn, it being only necessary, for this purpose, to apply slight lateral pressure to the handle formed by the parts 5, 6, and to give the cone a slight rotary movement at the same time. This removal is accomplished in almost an instant of time, whereas, by the old method it is necessary to melt out the cone of wax whose place and function are substituted by my metal cone 1. Besides this, the whole of the investment is left clean and clear of any portion of the wax. The hole left in the investment then serves for reception of the porcelain or other material which is to form the inlay, and which requires to be heated to a certain degree.

The function of the enlarged head of the pin in addition to holding the wax model, is

to prevent the investin material from entering the cone when thel atter is being inserted therein. In View of its secondary functlon, the pin is commonly denoted a sprue pin, or

I sprue-hole pin.

0 as described.

2. The improved dental implement, comprising a hollow cone having a'hole in the apex and a rigidbracke't Within the same, a pin having an enlarged head and a shank adapted to slide in said hole and through the 20 bracket, -a handle proper which is rigidly connected with the bracket, and a pin clasp comprising a plate pivoted to the handle and adapted for engagement with the pin, for

holding its enlarged head in contact With the 25 outer side of the cone apex,'substantially as described. 7

CHAS. o. MURRAY.

Witnesses:

FRAN K E. Gonwm,

E} O. WILLIAMs. 

